1. Field of the Invention
The invention relates to the field of milking dairy animals and more particularly to a combination of a teat cup and a flexible milk tube having multiple ducts. The invention also relates to a method of monitoring the integrity of such a milk tube and to a coupling piece for connecting of the milk tube to a further component.
2. Description of the Related Art
Devices are known for automatically milking a dairy animal, such as a cow, in which a teat cup is connected to a flexible milk tube. The milk tube may serve for discharging milk obtained by milking, applying vacuum to an end of a teat of the cow, applying a pulsating vacuum to the circumferential surface of the teat of the cow, and for supplying clean air to the teat cup. For these functions, the relevant flexible milk tube may be provided with a plurality of ducts. Such a device is known from WO-96/17509, the content of which is incorporated herein by reference, which discloses a case with three ducts. These three ducts are separated from each other. This means that the ducts are capable of fulfilling different functions. A main duct substantially applies continuous vacuum and discharges the milk, a first secondary duct applies the pulsating vacuum, and a second secondary duct supplies the air. Each of the main and secondary ducts is confined by its own duct wall. In fact, there are thus formed three separate tubes that are interconnected over a substantial part of their length.
The known flexible milk tubes have certain disadvantages, including the fact that they may occupy a relatively large amount of space. This may be of particular relevance in cases where each teat cup is separately connected to the milking device and vacuum source. In such cases, a plurality of milk tubes from each of the four udder quarters of an animal may run together over a considerable distance e.g. along a part of the robot arm of an automatic milking robot. Another disadvantage of a plurality of separate tubes is that they can easily tangle and snag. In cases where the tubes are physically connected together, the resulting tube bundle is generally non symmetrical and may always tend to bend in one direction. In certain circumstances, this may be undesirable.